Type a gelatin capsule containing pufa in free acid form

ABSTRACT

A pharmaceutical formulation comprising at least one omega-3 polyunsaturated fatty acid in free acid form or a pharmacologically acceptable derivative thereof is contained in a soft gelatin capsule characterised in that the capsule comprises gelatin extracted by an extraction process comprising acid pre-treatment of a collagen source. One advantage of the present invention over a soft gelatin capsule containing the same formulation but comprising gelatin extracted by an extraction process comprising alkali pre-treatment of the collagen source is that the present invention does not harden significantly over time and thus has a longer shelf life.

The present invention relates to a soft gelatin capsule and, inparticular, to a soft gelatin capsule containing a pharmaceuticalformulation comprising at least one omega-3 polyunsaturated fatty acidin free acid form or a pharmacologically acceptable derivative thereof.

Gelatin is a heterogeneous mixture of water-soluble proteins of highmolecular weight extracted from a number of sources of collagen suchbovine bones and hide, pig skin or fish skin. Broadly speaking, thereare two types of gelatin, Type A gelatin and Type B gelatin, dependingon the method of extraction.

According to “Gelatin Processing” (US National Organic Standards BoardTechnical Advisory Panel Review; 1 Mar. 2002), Type A gelatin isextracted following an acid pre-treatment process and porcine gelatin isusually extracted in this way. Pigskins are dehaired and degreased andthe resultant skin is passed through a chopper or macerator to cut theskin into uniform sizes. The skin is then soaked at a pH of 1 to 4 witha food-grade mineral acid such as hydrochloric acid, phosphoric acid orsulphuric acid for 8 to 30 hours. The acid-treated pigskin is thenwashed with water to remove impurities and extracted with hot water. Theextract is filtered through an anion-cation exchange column to reduceash or mineral levels. The gelatin extract is vacuum concentrated orultra filtered to a concentration between 15 to 35%, filtered, pHadjusted to between 3.5 and 6, and evaporated to 50% solids. The residueis chilled, extruded, dried and milled to the required particle size andthen packaged. It is also known to pre-treat bovine ossein(de-mineralised bone) with acid prior to extraction of the gelatinalthough bovine ossein is more commonly pre-treated with alkali.

Type B gelatin is extracted following an alkali pre-treatment processand bovine gelatin is usually extracted in this way (ibid). Bones arecrushed, cooked, centrifuged and dried. The extracted bone is degreasedprior to gelatin extraction and de-mineralised with 4 to 6% hydrochloricacid for a period of 5 to 7 days. The ossein is washed repeatedly withwater to remove impurities and then treated with 1 to 4% lime (calciumhydroxide) slurry to adjust the pH to about 12 for periods of 35 to 70days with agitation and weekly lime changes to remove non-collagencomponents. The ossein is then washed and mineral acid is added toneutralise excess lime and adjust the pH to 3. The final pH after allwash operations is between 5 and 7. De-mineralised hot water is thenused to extract the gelatin. The liquid gelatin solution may be filteredthrough a cellulose/diatomaceous earth plate and frame filter anddeionised using an anionic-cationic resin bed. The resin solution isevaporated to a concentration between 15 to 45%. The concentratedgelatin is filtered, pH adjusted to between 5 and 7, sterilised, cooledand air-dried. It is then milled to the required size and packaged. Thealkaline process may take up to 20 weeks.

Gelatin is used, for example, to encapsulate various foods andnutritional supplements but especially medicines for oral administrationto treat a number of conditions. Plasticizers such as glycerine may beadded to gelatin to produce soft gelatin capsules. Formaldehyde andother aldehydes may be used to harden gelatin capsules and enable themto pass from the stomach to the intestines. The vast majority of softgelatin capsules are manufactured from Type B, e.g. bovine, gelatin.

Omega-3 polyunsaturated fatty acids such as 5, 8, 11, 14,17-eicosapentaenoic acid (or “EPA”) or 4, 7, 10, 13, 16,19-docosahexaenoic acid (or “DHA”) are well known to be useful in thetreatment of inflammatory bowel disease (or “IBD”) (see, for example,EP-A-0244832, EP-A-0289204, EP-A-0311091 and WO-A-93/21912, thedisclosures of which are incorporated herein by reference).WO-A-96/36329 (Buser et al; published on 21 Nov. 1996) discloses atreatment of IBD involving oral administration of hard gelatin capsulescontaining a formulation that comprises a mixture of EPA and DHA. Eachcapsule is film coated with Eudragitrm NE 30-D which is an entericmaterial comprising poly(ethylacrylate-methylmethacrylate) having anaverage molecular weight of about 800,000. The capsules pass through thestomach and then disintegrate and release the contents in the smallintestine. Results indicate that clinical relapses in Crohn's diseasemay be prevented by the oral administration of such coated capsules.

It is disclosed in U.S. Pat. No. 2,870,062 (Scherer et al; published on20 Jan. 1959) that “standard gelatin capsules” disintegrate in contactwith deliquescent or hygroscopic chemicals, such as liquid non-ionicdetergents, salts of strong acids and bases, choline chloride andchloral hydrate, encapsulated within. U.S. Pat. No. 2,870,062 disclosesthe use of capsules made from specially selected low viscosity, highBloom strength gelatin prepared from acid treated bone precursor. Suchcapsules do not appear to disintegrate when left in contact withdeliquescent or hygroscopic chemicals.

EP-A-0100052 (Yu; published on 8 Feb. 1984) discloses soft gelatincapsules containing PGE-type prostaglandin fatty acid compositions.Comparative studies appear to indicate that soft gelatin capsules madefrom Type B gelatin accelerate degradation of the prostaglandincomposition whereas soft gelatin capsules made from Type A gelatinretain the stabilising effect of the solvent in which the prostaglandinfatty acids are dissolved.

U.S. Pat. No. 6,234,464 (Krumbholz et al; published on 22 May 2001)discloses microencapsulated unsaturated fatty acids or fatty acidcompounds or mixtures thereof. The wall of the microcapsules comprisestwo layers. The inner layer is composed of bone gelatin (gelatin A orgelatin B), casein or an alginate or by a derivative or salt thereof andthe outer layer is composed of gelatin B, gum arabic, pectin or chitosanor a derivative or salt thereof. The unsaturated fatty acid may be anomega-3 fatty acid or and ethyl ester or glyceride thereof. U.S. Pat.No. 6,234,464 exemplifies microencapsulated 95% EPA ethyl ester in whichthe wall of each microcapsule comprises an inner/outer layer combinationof gelatin A/gum arabic, gelatin A/pectin or gelatin A/gelatin B.

The inventors have discovered that, under certain conditions, softgelatin capsules made from Type B gelatin and containing apharmaceutical formulation comprising omega-3 polyunsaturated fattyacids can harden over time, even in the presence of plasticizers in thegelatin and have concluded that the hardening is due to chemicalinteraction between the omega-3 polyunsaturated fatty acid formulationand the gelatin itself. Such a hardening effect can reduce the shelflife of the capsules as, when the hardened capsules are administeredorally, they pass not only through the stomach but also though the smallintestine and may even pass through a substantial part of the largeintestine before the capsule disintegrates and the pharmaceuticalformulation is released. If the capsules are being administered as atreatment of IBD then release of the omega-3 polyunsaturated fatty acidformulation beyond the small intestine will not be effective in thistreatment. It is, therefore, an object of preferred embodiments of thepresent invention to provide a soft gelatin capsule containing anomega-3 polyunsaturated fatty acid formulation that displays a reducedhardening rate and thereby has an increased shelf life when compared toexisting soft gelatin capsules containing omega-3 polyunsaturated fattyacids.

Disintegration of a soft gelatin capsule in vivo occurs not only thoughdissolution in an aqueous medium but also through the action ofproteases on the gelatin. However, the chemical interaction between theomega-3 polyunsaturated fatty acid and the gelatin is uncontrolled andmay continue throughout the shelf life of the product. In addition, acoating on the capsule will usually hinder the action of the proteasesthereby reducing their effectiveness.

According to a first aspect of the present invention, there is provideda soft gelatin capsule containing a pharmaceutical formulationcomprising at least one omega-3 polyunsaturated fatty acid (“PUFA”) infree acid form or a pharmacologically acceptable derivative thereofcharacterised in that the capsule comprises gelatin extracted by anextraction process comprising acid pre-treatment of a collagen source.

One advantage of this type of soft gelatin capsule is that the rate ofhardening is significantly less than that for existing soft gelatincapsules (containing an omega-3 polyunsaturated fatty acid formulation)comprising gelatin extracted by an extraction process comprising alkalipre-treatment of a collagen source. The reduced rate of hardeningtranslates into an increased shelf life for the capsules. A furtheradvantage is that it is possible to move away from gelatin made frombovine bones and hides. In recent years, there has been some concernregarding the possible transmission of spongiform encephalopathies suchas bovine spongiform encephalopathy (or “BSE”) to humans. Type Agelatin, or gelatin extracted by an extraction process comprising acidpre-treatment of a collagen source, is usually made from pig skin and,thus, the use of such gelatin for the manufacture of soft gelatincapsules avoids any risk of contracting BSE from bovine Type B gelatin.

The decrease in hardening rate is surprising and unexpected as porcinegelatin (usually Type A gelatin) and bovine gelatin (usually Type Bgelatin) have basically the same chemical structure in that the aminoacid residues in both types of gelatin are essentially identical.Therefore, the skilled person would not expect the two types of gelatinto interact differently with the same omega-3 polyunsaturated fattyacid.

The omega-3 polyunsaturated fatty acid is preferably present in the formof the free acid. However, pharmacologically acceptable derivatives mayalso be used. Examples of suitable derivatives include triglycerides,esters (such as ethyl ester), amides, complexes (e.g. with bile salts,cholesterol or chitosan) and salts (such as sodium or potassium salts).In preferred embodiments, the formulation consists essentially of atleast one omega-3 polyunsaturated fatty acid in free acid form or apharmacologically acceptable derivative thereof but usually furthercomprises additives such as antioxidants, e.g. α-tocopherol.

Preferably, the formulation comprises 5, 8, 11, 14, 17-eicospentenoicacid (or “EPA”). EPA may present in an amount of at least about 50 wt %and preferably between from about 50 wt % to about 60 wt % of theformulation although it may also be desirable to have EPA present in anamount of at least about 90 wt % of the formulation for certainapplications and/or to minimise the number of capsules needed to betaken to provide a therapeutically active dose.

The formulation may comprise 4, 7, 10, 13, 16, 19-docosahexaenoic acid(or “DHA”). DHA may be present in an amount of between from about 20 wt% to about 30 wt % of the formulation.

The soft gelatin capsule preferably comprises between from about 100 mgto about 2000 mg of said formulation. At present, two embodiments of thecapsule are preferred, the first embodiment comprising about 500 mg ofsaid formulation and intended for use, for example, with children andthe second embodiment comprising about 1000 mg intended for adult use.

The gelatin used is preferably at least one selected from the groupconsisting of porcine gelatin, bovine gelatin and fish gelatin, providedthat the gelatin has been extracted by an extraction process comprisingacid pre-treatment of the relevant collagen source. Mixtures of thesegelatins may also be used.

The wall of each of the soft gelatin capsules of the present inventionusually consists of only one layer.

Soft gelatin capsules of the present invention may be used in thetreatment or prophylaxis of chronic inflammatory conditions such asinflammatory bowel disease,

Crohn's disease, ulcerative colitis, rheumatoid arthritis, psoriasis orBehcet's syndrome; hyperlipidaemia or hypertriglyceridaemia; asthma;bipolar disorder; and neoplastic disease such as prostate cancer orbowel cancer. In certain preferred embodiments, the soft gelatin capsulewill be used to treat or prevent IBD or Crohn's disease. In addition,the capsules may be used to prevent post-operative recurrence of Crohn'sdisease.

If administered parenterally, immunosuppressants (e.g. methotrexate orcyclosporin) or antineoplastic agents (e.g. methotrexate) often haveadverse systemic side effects. GB0413729.5 (filed on 18 Jun. 2004)describes the use of PUFA or a pharmacologically acceptable salt orderivative thereof in combination with at least one of animmunosuppressant and an antineoplastic agent, said agent(s) having atleast one amino acid residue, or a pharmacologically acceptable salt orderivative thereof in the manufacture of a medicament for the treatmentof intestinal conditions. GB0413730.3 (filed on 18 Jun. 2004) describesthe use of PUFA or a pharmacologically acceptable salt or derivativethereof in combination with at least one of an immunosuppressant and anantineoplastic agent or a pharmacologically acceptable salt orderivative thereof in the manufacture of a medicament for the topicaltreatment of intestinal conditions. The effect of the PUFA in the usesdisclosed in GB0413730.3 and GB0413729.5 is to increase the oralbioavailability of the immunosuppressant and antineoplastic agent,thereby allowing less agent(s) to be administered and reducing the sideeffects. The disclosures of GB0413729.5 and GB0413730.3 are incorporatedherein by reference.

The soft gelatin capsules of the present invention may be used toprovide the PUFA to achieve this sparing effect for immunosuppressantssuch as methotrexate, cyclosporin, dactinomycin, 6-mercaptopurine,cyclophosphamide, mycophenolate, daclizumab, muromonab, predisolone,sirolimus, dexamethasone, rapamycin, FK506, mizoribine, azathioprine,tacrolimus and infliximab and for antineoplastic agents such asmethotrexate, dactinomycin, fluorouracil, bleomycin, etoposide, taxol,vincristine, doxorubicin, cisplatin, daunorubicin and VP-16.

EP-A-1054678 discloses the use of PUFAs as steroid sparing agents. Thesoft gelatin capsule of the present invention could be used to providethe PUFA to spare steroids such as budesonide or prednisolone. Thedisclosure of EP-A-1054678 is incorporated herein by reference.

The capsule preferably delays release of the formulation until afterpassage through the stomach. Release preferably occurs after passagebeyond the pancreatic duct in the duodenum and, more preferably, in theileum. Preferably, release should not occur after the mid-jejunum.Release is typically delayed for at least 30 minutes after oraladministration and preferably for between 30 to 60 minutes at pH 5.5.Release of the formulation begins after the integrity of the capsulewall is compromised, i.e. after dissolution or perforation of thegelatin wall. If release occurs due to the gelatin capsule becomingporous, then release may also be sustained which may be advantageous,especially in the treatment of IBD or Crohn's disease. Release may bedelayed by coating the capsule with at least one enteric material thatis resistant to dissolution in a time dependent and/or pH dependentmanner. Alternatively or additionally, at least one such entericmaterial is integrated within the gelatin of the capsule. Preferably, atime but not pH dependent release coating material is used. A preferredenteric material is a neutral polyacrylate such aspoly(ethylacrylate-methylmethacrylate), especially Eudragit NE 30-D(Rohm Pharma GmbH) which has an average molecular weight of about800,000 and is an example of a time but not pH dependent release coatingmaterial.

According to a second aspect of the present invention, there is provideduse of gelatin extracted by an extraction process comprising acidpre-treatment of a collagen source in the manufacture of a medicamentcomprising at least one soft gelatin capsule as defined in the firstaspect for the oral treatment or prophylaxis of a condition selectedfrom chronic inflammatory conditions, hyperlipidaemia,hypertriglyceridaemia, asthma, bipolar disorder and neoplastic disease.The medicament has particular application in the treatment orprophylaxis of inflammatory bowel disease (“IBD”) or Crohn's disease.The medicament may comprise at least one soft gelatin capsule having anyof the preferred features discussed above in any appropriatecombination.

According to a third aspect of the present invention, there is provideda process for the manufacture of a soft gelatin capsule containing apharmaceutical formulation comprising at least one omega-3polyunsaturated fatty acid in free acid form or a pharmacologicallyacceptable derivative thereof, said process comprising encapsulatingsaid pharmaceutical formulation in gelatin extracted by an extractionprocess comprising acid pre-treatment of a collagen source.

According to a fourth aspect of the present invention, there is provideduse of gelatin extracted by an extraction process comprising acidpre-treatment of a collagen source in a soft gelatin capsule containinga pharmaceutical formulation comprising at least one omega-3polyunsaturated fatty acid in free acid form or a pharmacologicallyacceptable derivative thereof to improve resistance of the soft gelatincapsule to chemical interaction with the formulation. Preferably, saidresistance is greater than that of a soft gelatin capsule containing apharmaceutical formulation comprising at least one omega-3polyunsaturated fatty acid in free acid form or a pharmacologicallyacceptable derivative thereof in which the gelatin consists essentiallyof gelatin extracted by an extraction process comprising alkalipre-treatment of a collagen source.

According to a fifth aspect of the present invention, there is provideduse of gelatin extracted by an extraction process comprising acidpre-treatment of a collagen source in a soft gelatin capsule containinga pharmaceutical formulation comprising at least one omega-3polyunsaturated fatty acid in free acid form or a pharmacologicallyacceptable derivative thereof to improve shelf life of the soft gelatincapsule. Preferably, said shelf life is greater than that for a softgelatin capsule containing a pharmaceutical formulation comprising atleast one omega-3 polyunsaturated fatty acid in free acid form or apharmacologically acceptable derivative thereof in which the gelatinconsists essentially of gelatin extracted by an extraction processcomprising alkali pre-treatment of a collagen source.

The soft gelatin capsule may be used in the treatment or prophylaxis ofIBD and, in particular, Crohn's disease. In such treatment or the othertreatments listed above, the daily dosage of the formulation would beset by the doctor in charge of the patient and would depend on a numberof factors such as age. Usually, between from about 1 g to about 8 g ofthe formulation is administered to the patient per day, particularly inthe treatment of IBD or Crohn's disease. Administration may be in theform of a plurality of soft gelatin capsules according to the firstaspect of the present invention. The total number of capsulesadministered daily will depend on the amount of the formulation in eachcapsule. Thus, for example, a daily dose of 4 g of formulation might beadministered in the form of either 8 500 mg capsules or 4 1000 mgcapsules and a daily dose of 8 g of formulation might be administered inthe form of 8 1000 mg capsules.

According to a sixth aspect of the present invention, there is provideda method of treatment or prophylaxis of a condition selected fromchronic inflammatory conditions, hyperlipidaemia, hypertriglyceridaemia,asthma, bipolar disorder and neoplastic disease comprising administeringa therapeutically effective amount of a pharmaceutical formulationcomprising at least one omega-3 polyunsaturated fatty acid in free acidform or a pharmacologically acceptable salt thereof per day in the formof a plurality of soft gelatin capsules according to the first aspect ofthe present invention. Where the condition to be treated or prevented isIBD or Crohn's disease, the therapeutically effective amount is usuallyfrom about 1 g to about 8 g. The capsules may have any of the preferredfeatures discussed above in any appropriate combination.

The following is a description, by way of example only, of a presentlypreferred embodiment of the present invention.

Type A gelatin capsules were formed and simultaneously filled with anomega-3 polyunsaturated fatty acid formulation in a known manner. Type Aporcine gelatin powder was mixed with water and plasticizer and thenheated to form a molten gelatin mass. Two thin ribbons of the moltengelatin were produced and passed between two die rolls which determinedthe shape of the capsules. The formulation was injected between the twogelatin ribbons just before the die rolls sealed the capsules togetherby application of heat and pressure. The resulting capsule was thendried to the required moisture content.

The stability of the Type A gelatin capsules produced in this manner wascompared with that for the Type B gelatin capsules produced using thesame process. Batches of both capsules were stored for different periods(3 months, 6 months, 9 months and 12 months) and at differenttemperatures (25° C., 30° C. and 40° C.) and then the disintegrationtimes of the capsules in purified water at 37° C. according to Ph. Eur.were measured. The results are indicated in Table 1.

TABLE 1 Storage Temp Capsule (° C.) 0 months 3 months 6 months 9 months12 months Type B gelatin 25 7 min 9 min 9 min 6 min 10 min (Bovine) 30 7min 9 min 20 min  n.p. Insoluble 40 7 min Insoluble Insoluble n.p. n.p.Type A gelatin 25 6 min 6 min 7 min 6 min  7 min (Porcine) 30 6 min 7min 8 min n.p. 10 min 40 6 min 8 min 10 min  n.p. n.p.

It should take no longer than 30 min for a soft gelatin capsule todisintegrate if it is to release its contents effectively. Therefore, ifa capsule failed to disintegrate in 30 min, it was deemed “insoluble”.The term “n.p.” indicated that the test was “not performed”.

The results indicate that, for the Type B (bovine) gelatin capsulesstored at a given temperature, there is a general increase indisintegration time as the storage time increases. In addition, for theType B (bovine) gelatin capsules stored for a given time, there is ageneral increase in disintegration time as the storage temperatureincreases. These results are consistent with the omega-3 polyunsaturatedfatty acid interacting chemically with the Type B gelatin resulting in ahardening of the capsule wall.

In contrast, disintegration time is not substantially increased for theType A (porcine) gelatin capsules as either the storage time or storagetemperature increases. These results would appear to indicate that thedegree of hardening is significantly less for Type A (porcine) gelatincapsules than for Type B (bovine) gelatin capsules.

In particular, attention is drawn to the disintegration results for theType B (bovine) gelatin capsules stored at 30° C. for 12 months and at40° C. for 3 months and 6 months as these capsules have been classifiedas “insoluble” whereas the corresponding Type A (porcine) gelatincapsules took no more than 10 minutes to dissolve.

It will be appreciated that the invention is not restricted to thedetails described above with reference to the preferred embodiments butthat numerous modifications and variations can be made without departingfrom the spirit or scope of the invention as defined by the followingclaims.

1.-34. (canceled)
 35. A soft gelatin capsule comprising Porcine Type Agelatin, said capsule containing a pharmaceutical formulationcomprising: 5, 8, 11, 14, 17-eicosapentaenoic acid (or “EPA”) in freeacid form and 4,7, 10, 13, 16, 19-docosahexarnoic acid (or “DHA”) infree acid form, wherein the soft gelatin capsule comprising Porcine TypeA gelatin exhibits a longer shelf life as compared to soft gelatincapstiles comprising Type B gelatin, Bovine Type A gelatin or Fish TypeA gelatin, wherein said soft gelatin capsules comprising Type B gelatin,Bovine Type A gelatin or Fish Type A gelatin contain a pharmaceuticalformulation comprising at least one omega-3 polyunsaturated fatty acidin free acid form, wherein the at least one omega-3 polyunsaturatedfatty acid is selected from the group consisting of EPA in free acidform and DHA in free acid form, and wherein the shelf life is determinedby storing said soft gelatin capsule comprising Porcine Type A gelatinand said soft gelatin capsules comprising Type B gelatin, Bovine Type Agelatin or Fish Type A gelatin for 3 months at a temperature of 40° C.;disintegrating each of the capsules in water at 37° C.; and measuringdisintegration times of each capsule to determine the shelf life of eachcapsule.
 36. The soft gelatin capsule according to claim 35, wherein theEPA is present in an amount of at least about 50 wt % of theformulation.
 38. The soft gelatin capsule according to claim 35, whereinthe EPA is present in an amount of at least about 50 wt % to about 60 wt% of the formulation.
 39. The soft gelatin capsule according to claim35, wherein the EPA in free acid form is present in an amount of atleast about 90 wt % of the formulation.
 39. The soft gelatin capsuleaccording to claim 35, wherein the DHA is present in an amount of atleast about 20 wt % to about 30 wt % of the formulation.
 40. The softgelatin capsule according to claim 35 comprising between from about 100mg to about 2000 mg of said formulation.
 41. The soft gelatin capsuleaccording to claim 40 comprising about 500 mg of said formulation. 42.The soft gelatin capsule according to claim 40 comprising about 1000 mgof said formulation.
 43. Use of the soft gelatin capsule according toclaim 35 in the treatment or prophylaxis of a condition selected fromthe group consisting of chronic inflammatory condition, hyperlipidaemia,hypertriglyceridaemia, asthma, bipolar disorder and neoplastic disease.44. The use according to claim 43, wherein the chronic inflammatorycondition is selected from the group consisting of inflammatory boweldisease, Crohn's disease, ulcerative colitis, rheumatoid arthritis,psoriasis and Behcet's syndrome.
 45. The use according to claim 43,wherein the neoplastic disease is prostate cancer or bowel cancer.